Create RestaurantController, add GET (index) and POST (create)

[Arik]

Create RestaurantController, add GET (index) and POST (create)

Acceptance Criteria:

• There is a controller file RestaurantController.java
  in the expected directory.
• In RestaurantController.java there is
  code for a GET /api/Restaurant/all endpoint
  that returns a JSON list of all Restaurants in the database.
  (We sometimes call this an index action since it lists all
  items in the database.)
• In RestaurantController.java there is
  code for a POST /api/Restaurant/post endpoint
  that can be used to create a new entry in the table. (This
  is a create action.)
• The Swagger-UI endpoints for these are well documented so that
  any member of the team can understand what they are for and
  how to use them.
• The POST endpoint works as expected, in the sense that new
  records can be added to the database (on localhost).
• The GET endpoint works as expected, in the sense that the new
  records that are added show up (on localhost).
• The GET and POST endpoints work as expected when the
  app is deployed to Dokku.
• There is full test coverage (Jacoco) for the methods in
  RestaurantController.java
• There is full mutation test coverage (Pitest) for the methods in
  RestaurantController.java